var request;

function createRequest()
{
  try
  {
    request = new XMLHttpRequest();
  }
  catch (trymicrosoft)
  {
    try
    {
      request = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (othermicrosoft)
    {
      try
      {
        request = new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch (failed)
      {
        request = false;
      }
    }
  }

  if (!request)
    alert("Error initializing XMLHttpRequest!");
}

function sendRequest(url)
{
    // Create a request object
    createRequest();		

    // Setup (initialize) the request
    request.open("GET", url, true);
    request.onreadystatechange = updatePage;
    request.send(null);
}

function sendPostRequest(url, parameters, actionPage)
{
    // Create a request object
    createRequest();
    
    if (request.overrideMimeType)
    {
      // set type accordingly to anticipated content type
      //request.overrideMimeType('text/xml');
      request.overrideMimeType('text/html');
    }		

    request.onreadystatechange = actionPage;
    request.open('POST', url, true);
    request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    request.setRequestHeader("Content-length", parameters.length);
    request.setRequestHeader("Connection", "close");
    request.send(parameters);
}

function updateThemData(formId)
{
	var thisForm = document.getElementById(formId);
	
	if(thisForm)
	{
		var form_thema = thisForm.thema.value;
		var form_eid = thisForm.eid.value;
		var form_tblrow = thisForm.tblrow.value;
		
		if(form_thema < 0)
		{
			alert("Bitte wählen Sie die Kategorie des Begriffs aus.");
			return;
		}
		
		var poststr = "form_thema=" + encodeURIComponent(form_thema)
			+ "&form_eid=" + encodeURIComponent(form_eid)
			+ "&form_tblrow=" + encodeURIComponent(form_tblrow);
		
		sendPostRequest('begriff_edit_thema.php', poststr, updatePage);
	}
}

function updateLevelData(formId)
{
	var thisForm = document.getElementById(formId);

	if(thisForm)
	{
		var form_level = thisForm.level.value;
		var form_eid = thisForm.eid.value;
		var form_tblrow = thisForm.tblrow.value;
		
		if(form_level < 1)
		{
			alert("Bitte wählen Sie die Schwierigkeitsstufe des Begriffs aus.");
			return;
		}
		
		var poststr = "form_level=" + encodeURIComponent(form_level)
			+ "&form_eid=" + encodeURIComponent(form_eid)
			+ "&form_tblrow=" + encodeURIComponent(form_tblrow);
		
		sendPostRequest('begriff_edit_level.php', poststr, updatePage);
	}
}

function updatePage()
{
   if (request.readyState == 4)
   {
     if (request.status == 200)
     {
     		if(request.responseText.indexOf("|") > 0)
				{
					var response = request.responseText.split("|");
					var tablerow = document.getElementById(response[0]);
					
					if(tablerow)
					{
						tablerow.innerHTML = response[1]; //Zeichen
					}
				}
				else
				{
					alert(request.responseText);
				}
     }
     else
     {
	   		alert("Sorry, could not get a answer from the server. Please retry in a few minutes.");
     }
   }
}

function addLink_thema(eid,linkid)
{
	sendRequest("begriff_edit_thema_form.php?eid="+eid+"&linkid="+linkid);
}

function addLink_level(eid,linkid)
{
	sendRequest("begriff_edit_level_form.php?eid="+eid+"&linkid="+linkid);
}